Dewey R E, Siedow J N, Timothy D H, Levings C S
Department of Crop Science, North Carolina State University, Raleigh 27695.
Science. 1988 Jan 15;239(4837):293-5. doi: 10.1126/science.3276005.
The Texas male-sterile cytoplasm (cms-T) of maize carries the cytoplasmically inherited trait of male sterility. Mitochondria isolated from cms-T maize are specifically sensitive to a toxin (BmT-toxin) produced by the fungal pathogen Bipolaris maydis, race T, and the carbamate insecticide methomyl. A mitochondrial gene unique to cms-T maize, which produces a 13-kilodalton polypeptide associated with cytoplasmic male sterility, was expressed in Escherichia coli. After addition of BmT-toxin or methomyl, inhibition of whole cell respiration and swelling of spheroplasts were observed in Escherichia coli cultures producing the novel mitochondrial protein; these effects are similar to those observed with isolated cms-T mitochondria. The amino-terminal region of the 13-kilodalton polypeptide appears to be essential for proper interaction with the BmT-toxin and methomyl. These results implicate the 13-kilodalton polypeptide in conferring toxin sensitivity to mitochondria of cms-T maize.
玉米的德克萨斯雄性不育细胞质（cms-T）具有细胞质遗传的雄性不育特性。从cms-T玉米中分离出的线粒体对真菌病原体玉米小斑病菌T小种产生的毒素（BmT毒素）以及氨基甲酸酯类杀虫剂灭多威具有特异性敏感性。在大肠杆菌中表达了cms-T玉米特有的一个线粒体基因，该基因产生一种与细胞质雄性不育相关的13千道尔顿多肽。在产生这种新型线粒体蛋白的大肠杆菌培养物中，加入BmT毒素或灭多威后，观察到全细胞呼吸受到抑制，原生质球肿胀；这些效应与在分离的cms-T线粒体中观察到的效应相似。13千道尔顿多肽的氨基末端区域似乎对于与BmT毒素和灭多威的正确相互作用至关重要。这些结果表明，13千道尔顿多肽使cms-T玉米的线粒体具有毒素敏感性。
